Gate driving method and circuit for liquid crystal display

Abstract

A gate driving method for a liquid crystal display (LCD) and a gate driver thereof are provided. The LCD has a plurality of scan lines. The method starts by generating a gate driving signal. A correction signal is superposed to the gate driving signal to generate a corrected gate driving signal and to reduce a high voltage level of the gate driving signal, wherein a polarity of the correction signal is opposite to a polarity of the gate driving signal. The corrected gate driving signal is then outputted to drive one of the corresponding scan lines.

What is claimed is:  
     
       1. A gate driving method for a liquid crystal display, the liquid crystal display comprising a plurality of scan lines, the gate driving method for the liquid crystal display comprising:
 providing an independent gate driving signal to drive one of the corresponding scan lines; and 
 providing an independent correction signal to said one of the corresponding scan lines and pulling down a high voltage level of the independent gate driving signal to a first voltage level which is smaller than the high voltage level and greater than a low voltage level of the independent gate driving signal in response to an amplitude of the independent correction signal before the independent gate driving signal is switched from the high voltage level to the low voltage level and before a next independent gate driving signal is provided to a next corresponding scan line, wherein the first voltage level is determined by the amplitude of the independent correction signal, 
 wherein said one of the corresponding scan lines is continuously driven by the pulled down gate driving signal until a gate output enable signal is provided for generating the next independent gate driving signal, a polarity of the independent correction signal is opposite to a polarity of the independent gate driving signal, the independent gate driving signal is a positive voltage square wave, and the independent correction signal is a negative voltage square wave, 
 wherein a high voltage level of the independent correction signal is equal to the low voltage level of the independent gate driving signal, and a low voltage level of the independent correction signal is small than the low voltage level of the independent gate driving signal, 
 wherein the independent gate driving signal and the independent correction signal are provided to the said one of the corresponding scan lines in sequence, and are superposed with each other on the said one of the corresponding scan lines. 
 
     
     
       2. A method of generating a gate driving signal of a liquid crystal display, so that the gate driving signal drives a scan line of the liquid crystal display, the method of generating the gate driving signal of the liquid crystal display comprising:
 providing an independent positive voltage square wave signal to the scan line; 
 performing a trimming operation to the independent positive voltage square wave signal at a first preset time before a declining edge of the independent positive voltage square signal, so as to reduce a high voltage level of the independent positive voltage square wave signal to a first voltage level which is smaller than the first voltage level and greater than a low voltage level of the independent positive voltage square signal; and 
 providing an independent negative voltage square wave signal to the scan line at a second preset time before the declining edge of the independent positive voltage square wave signal and before a next independent positive voltage square wave signal is provided to a next scan line, and further pulling down the high voltage level of the independent positive voltage square wave signal from the first voltage level to a second voltage level which is smaller than the first voltage level and greater than the low voltage level in response to an amplitude of the independent negative voltage square wave signal, wherein the second voltage level is determined by the amplitude of the independent negative voltage square wave signal, 
 wherein the scan line is continuously driven by the pulled down positive voltage square wave signal until a gate output enable signal is provided for generating the next positive voltage square wave signal, and 
 wherein the second preset time is after the first preset time, 
 wherein a high voltage level of the independent negative voltage square wave signal is equal to the low voltage level of the independent positive voltage square signal, and a low voltage level of the independent negative voltage square wave signal is small than the low voltage level of the independent positive voltage square signal, 
 wherein the independent positive voltage square wave signal and the independent negative voltage square wave signal are provided to the scan line in sequence, and are superposed with each other on the scan line. 
 
     
     
       3. The method of generating the gate driving signal of the liquid crystal display of  claim 2 , wherein the independent negative voltage square signal is provided to the scan line immediately after the trimming operation.